The wavelength of exposure light used by an exposure apparatus has become shorter in recent years. An EUV exposure apparatus that uses extreme ultraviolet light (Extreme Ultraviolet Light: hereinafter abbreviated to EUV light) is on its way to being applied to the manufacture of a semiconductor device. In the EUV exposure apparatus, the EUV light is attenuated in the atmosphere. Accordingly, exposures are performed in a vacuum chamber.
When exposed in the vacuum chamber, a wafer is provided with energy from the EUV light and the like to generate heat. However, an object in a vacuum has a little amount of heat dissipation. There is a method in which a cooling mechanism is provided on an electrostatic chuck side that is in contact with the back surface side of the wafer as a method for dissipating energy. In the cooling mechanism, gas such as H2 is passed between the back surface of the wafer and the electrostatic chuck to release the heat of the wafer to the electrostatic chuck side.
However, if the output of a light source of EUV light is increased, even the cooling mechanism does not provide sufficient cooling. If cooling is not sufficiently provided, the wafer deforms. Accordingly, alignment accuracy and the like are reduced. Especially, due to the thermal effect of a shot that is being exposed, a thermal effect on an adjacent shot also occurs. Hence, an exposure process that suppresses the deformation of the wafer is desired.